1. Field of The Invention
The present invention relates generally to an apparatus for attenuating pressure pulsations in a hydraulic system. More particularly, the present invention relates to a compressor discharge muffler for air conditioning system of an automotive vehicle which attenuates the pressure pulsations propagated from the compressor of the air conditioning system and a method of manufacturing such a muffler.
2. Disclosure Information
Automotive heating, ventilating and air conditioning systems are known to be an annoying source of noise in a vehicle's passenger compartment. There are two components in the HVAC system that generate the majority of the noise: the air conditioning compressor in the refrigeration system and the blower in the air distribution system. The air conditioning compressor can produce a variety of steady state intransient noises depending on the ambient conditions, the type of compressor: (piston, rotary or scroll), number of cylinders in the engine and the associated drive ratio, and different engine operating conditions. The majority of the objectionable noise produced by the compressor results from the acoustical wave propagation of the air conditioning refrigerant through the air conditioning hoses in the engine compartment. These pulsations are readily transmitted through the various components in the air conditioning system, such as the evaporator or accumulator to become audible in the vehicle interior.
U.S. Pat. No. 5,101,931 discloses a compressor discharge muffler including a single expansion chamber and an impedance tube for attenuating pressure pulsations extending into the chamber. The outlet tube is disposed on a cylindrical wall of the housing and the impedance tube is secured into the chamber by a fitting. Given the very limited engine compartment space of today's vehicles, this type of muffler may present a space problem since the outlet and impedance tubes are disposed on different sides of the chamber. Furthermore, the use of a fitting to secure the impedance tube in the chamber is costly and complex. Therefore, it would be desirable to provide discharge muffler which presents a more efficient package design and which reduces the cost and complexity of prior art mufflers.